EarthTalk: Chlorine is in our tap water, but is it okay to drink?

Dear
EarthTalk:
I was wondering how toxic chlorine is, because my well water was just
chlorinated yesterday and today the smell is still strong. I have a
4-year-old daughter and I’m concerned. --
Rose Smith, via e-mail

According
to the U.S. Environmental Protection Agency (EPA), chlorine levels of
four parts per million or below in drinking water—whether from a
private well or municipal reservoir—are acceptable from a human
health standpoint. Inexpensive home drinking water test kits (from $5
on up) that can detect levels of chlorine and other elements in water
are widely available from online vendors. Administering the tests is
easy and can provide parents with a way to involve kids in science
for a practical purpose right at home.

Chlorine
was first used in drinking water to reduce waterborne infectious
diseases in Jersey City, New Jersey more than a century ago. It was
so effective at destroying potentially harmful bacteria and viruses
that the practice soon spread far and wide. Today some 98 percent of
water treatment facilities in the U.S. use some form of chlorine to
clean drinking water supplies. The American Water Works Association
(AWWA), a trade group representing water utilities across the
country, credits the presence of chlorine in drinking water with a 50
percent increase in life expectancy for Americans over the last
century. Indeed, some consider the chlorination of drinking water to
be one of history’s greatest public health achievements.

But
others aren’t so sure that any chlorine in drinking water should be
considered safe. Opponents of chlorination point to studies linking
repeated exposure to trace amounts of chlorine in water with higher
incidences of bladder, rectal and breast cancers. The problem lies in
chlorine’s ability to interact with organic compounds in fresh
water to create trihalomethanes (THMs), which when ingested can
encourage the growth of free radicals that can destroy or damage
vital cells in the body. Besides cancer, exposure to THMs has been
linked to other health issues including asthma, eczema, heart disease
and higher miscarriage and birth defect rates.

Those
with their own private wells who are skittish about chlorine have
other options for disinfecting their water. One baby step would be to
replace chlorine with chloramine, an ammonia derivative that doesn’t
dissipate into the environment as rapidly as chlorine and has a much
lower tendency to interact in bad ways with organic compounds in the
water. However, traces of chloramine in the water may not be to
everyone’s liking either, because it causes rashes after showering
in a small percentage of people and can apparently increase lead
exposure in older homes as it leaches the heavy metal off old
pipes.

Another
option, though somewhat costly, would be to purchase a machine to
purify the water. Ozonation units, which disinfect by adding ozone
molecules to water and leave no residues, start at around $9,000.
Another choice would be a UV light treatment machine—at $6,000 or
more—which cancels out viruses and bacteria by passing the water
through UV light rays. The Clean Water Store is a reputable vendor
and good online source for such water treatment equipment.

Perhaps
the most sensible and affordable approach is to filter
the water at the faucets and taps. Carbon-based tap- or
pitcher-mounted filters can work wonders in removing impurities from
drinking water. They can even be installed on shower heads for those
with sensitive skin.